package org.apache.lucene.search;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import java.io.IOException;

/**
 * Implements the wildcard search query. Supported wildcards are <code>*</code>,
 * which matches any character sequence (including the empty one), and
 * <code>?</code>, which matches any single character. Note this query can be
 * slow, as it needs to iterate over many terms. In order to prevent extremely
 * slow WildcardQueries, a Wildcard term should not start with one of the
 * wildcards <code>*</code> or <code>?</code>.
 * 
 * @see WildcardTermEnum
 */
public class WildcardQuery extends MultiTermQuery {
	private boolean termContainsWildcard;

	public WildcardQuery(Term term) {
		super(term);
		this.termContainsWildcard = (term.text().indexOf('*') != -1)
				|| (term.text().indexOf('?') != -1);
	}

	protected FilteredTermEnum getEnum(IndexReader reader) throws IOException {
		return new WildcardTermEnum(reader, getTerm());
	}

	public boolean equals(Object o) {
		if (o instanceof WildcardQuery)
			return super.equals(o);

		return false;
	}

	public Query rewrite(IndexReader reader) throws IOException {
		if (this.termContainsWildcard) {
			return super.rewrite(reader);
		}

		return new TermQuery(getTerm());
	}
}
